ATP stimulates human macrophages to kill intracellular virulent Mycobacterium tuberculosis via calcium-dependent phagosome-lysosome fusion
ATP stimulates human macrophages to kill intracellular virulent Mycobacterium tuberculosis via calcium-dependent phagosome-lysosome fusion
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DOI：
10.4049/jimmunol.167.6.3308
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发表时间：
2001-09-15
影响因子：
4.4
通讯作者：
Barton, JA
中科院分区：
文献类型：
--
作者：
Kusner, DJ;Barton, JA
结核病治疗的进展需要更多地了解这种疾病的发病分子机制和人类免疫反应。结核分枝杆菌感染的人巨噬细胞暴露于细胞外三磷酸腺苷(ATP)，可导致细菌死亡，但其分子机制仍未完全确定。在这项研究中，我们证明了ATP(E)诱导的对强毒结核分枝杆菌的杀菌活性需要感染的巨噬细胞胞内钙离子的增加。基于我们以前对人巨噬细胞原发感染的研究，我们假设ATP诱导的细胞内结核分枝杆菌杀伤的钙依赖与促进吞噬小体-溶酶小体融合有关。利用激光共聚焦扫描显微镜，我们证明了ATP(E)诱导了含有结核分枝杆菌的吞噬小体与溶酶体的融合，融合的定义是三种溶酶体蛋白和一种嗜酸性染料的积累。ATP(E)刺激吞噬小体-溶酶体融合对Ca~(2+)和磷脂酶D都有不同的需求，并与杀灭细胞内细菌高度相关。因此，关键的信号转导通路在两种不同的人类巨噬细胞抗结核活性模型之间是保守的：原始巨噬细胞的原发感染和稳定感染结核分枝杆菌的巨噬细胞的生理刺激。
Advances in therapy for tuberculosis will require greater understanding of the molecular mechanisms of pathogenesis and the human immune response in this disease. Exposure of Mycobacterium tuberculosis-infected human macrophages to extracellular ATP (ATP,) results in bacterial killing, but the molecular mechanisms remain incompletely characterized. In this study, we demonstrate that ATP(e)-induced bactericidal activity toward virulent M. tuberculosis requires an increase in cytosolic Ca2+ in infected macrophages. Based on our previous work with primary infection of human macrophages, we hypothesized that the Ca2+ dependence of ATP-induced killing of intracellular M. tuberculosis was linked to promotion of phagosome-lysosome fusion. Using confocal laser-scanning microscopy, we demonstrate that ATP(e) induces fusion of the M. tuberculosis-containing phagosome with lysosomes, defined by accumulation of three lysosomal proteins and an acidophilic dye. Stimulation of phagosome-lysosome fusion by ATP(e) exhibited distinct requirements for both Ca2+ and phospholipase D and was highly correlated with killing of intracellular bacilli. Thus, key signal transduction pathways are conserved between two distinct models of human macrophage antituberculous activity: primary infection of naive macrophages and physiologic stimulation of macrophages stably infected with M. tuberculosis.